21022989 has 24 divisors (see below), whose sum is σ = 31587360. Its totient is φ = 12362592.

The previous prime is 21022921. The next prime is 21022997. The reversal of 21022989 is 98922012.

It is a happy number.

It is not a de Polignac number, because 21022989 - 2⁸ = 21022733 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022909) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20122 + ... + 21140.

It is an arithmetic number, because the mean of its divisors is an integer number (1316140).

Almost surely, 2^21022989 is an apocalyptic number.

It is an amenable number.

21022989 is a deficient number, since it is larger than the sum of its proper divisors (10564371).

21022989 is a wasteful number, since it uses less digits than its factorization.

21022989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1081 (or 1058 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 21022989 is about 4585.0833144012. The cubic root of 21022989 is about 275.9930553808.

The spelling of 21022989 in words is "twenty-one million, twenty-two thousand, nine hundred eighty-nine".